Biomechanical variables including the masticatory forces on a dental implant, the implant geometry, and the resulting stresses and strains in interface tissues can determine the clinical success or failure of an endosseous dental implant. Up to now, inadequate characterization of masticatory forces on dental implant in various animal models has held back development of biomechanical design principles for dental implants. It is the goal of this research to measure in vivo forces on dental implants as functions of (1) bridgework over the implant and (2) the animal model. In the first year of the grant the aim will be to measure only the apical force component on a dental implant in vivo. To perfect the technique, a convenient implant geometry will be instrumented with strain gages, calcibrated, and then implanted into beagle dogs. Wires from the gages will be routed subcutaneously to each animal's back, and connected to appropriate bench-top electronics. Procedures will resemble those used by other workers who successfully measured in vivo strain in canine bones by strain gage methods. In years 2 and 3 of the grant, the aim will be to apply the methods developed in Year 1 to investigate how the force components in general on a dental implant depend upon (1) the type of bridgework over the implant, and (2) the animal model. To attack the latter problem completely, a commercially-available implantable telemetry system will be adapted for use with instrumented implants, since hard-wiring will be impractical in animals such as baboons or monkeys that are commonly used in implant research. Development of the capability to measure in vivo forces on dental implants in various animal models will lead to future experiments aimed at defining the interactions between implant-tissue biomechanics and clinical performance of implants.